The present invention is directed to video signal processing, and especially to processing composite video signals. A composite video signal format includes both chroma and luma signal components within the same frequency band. These chroma and luma signal components must be separated for effecting display of information conveyed by the composite video signal such as a video image frame. The process of separation is not an ideal process. Some chroma information may be identified as luma information, and some luma information may be identified as chroma information. Such misidentification may be manifested as artifacts that degrade picture quality.
For a still video picture separation of luma and chroma components signals may be carried out nearly ideally. Inter-frame comb filtering techniques (sometimes referred to as three dimensional luma-chroma separation, or 3DYC) are particularly successful filtering techniques because with a still picture succeeding frames carry substantially unchanged information. However, when there is motion in pictures, succeeding frames carry different information, sometimes significantly different information, thereby limiting the success of an inter-frame comb filtering technique.
There is a need for a signal treatment method that detects and accommodates motion in a picture. There is a need for a signal treatment method that can detect and accommodate motion between frames in composite video signals, especially in composite video signals encoded in a Phase Alternate Line (PAL) television signal standard format.